New process of preparing phenyl-oxalyl acetic-acid alkyl esters



i No Drawing.

Patented Dec. 31, 1929 UNITED STATES PATENT" OFFICE" RUFUS H. PRITCHETT, OF RENSSELAER, NEW YORK, ASSIGNOR T0 'WINTHRGP QHEMI- GAL COMPANY, INC., 0]? NEW YORK, N. Y., A CORPORATION OF NEW YORK NEW raocnss or PREPARING rnEnYL-oxALYL- ACEIIG-ACID 'ALZKYL. ns'rnns My invention relates to a new process of preparing phenyl-oxalyl-acetic acid alkyl esters of the general formula: I

' sunken-coon wherein R and R represent alkyl radicals.

I have found that these compounds are obtainable in a comparatively simple manner by causing a phenyl-acetic-acid-alkylester to react in an alcoholic solution and in the pres ence of sodium-aleoholate with an oxalic acid dialkylester, and converting the sodiumphenyl-oxalyl-acetic-acid-alkylester thus ob- COOLCaHs NaOOzHa wireor ribbon into the dry ether and a heating of the reaction mixture for many hours.

I have now found that in this reaction the ether can be replaced by dry alcohol. In comparison with the hitherto known process my new process offers several advantages, as for. instance lower expensesgsimplerhandhng of thealcdlitil iosolution in comparison with the Application filed January 19, 1929. serial No. 233,750.

handling of the ether solutiomehorte'r time of reaction, absence of the danger of fire hazard and explosion and finally a better yield.

' With my new process Ican easily'obtain a yield of about 80 per cent of the theory of phenyl-malonic-acidalkylester, whereas the process described by Wislice'nus generally does not yieldmore than about 50-60 per cent of the theory. p Inorder to describe my invention more fully, I give the following example, all'parts being by weight, the temperatures given in centigrades: i I

EmampZe.-To 315 parts of dry ethyl alcohol are added 23 parts of metallic sodium. The sodium reacts with the alcohol, producing sodium-ethylate When the sodium has completely reacted, the charge is cooled, and s 14.6 parts of diethylester of oxalic acid and 164 parts of phenyl-acetic-acid-ethylester are add.ed.- The reaction mixture is agitated to produce a thorough mixing. After a short time, a certain amount of heat is developed, and the sodium oxa'lyl phenyl-acetic-acidethylester crystallizes in a semi-solid mass.

The charge is allowed to stand over night.

The next morning the semi-solid mass is put into cold dilute muriatic acid, whereby the sodium-oxalyl -phenyl acetic-acid-ethylester is converted into the free oxalyl-phenyl-acetic-acid-ethylester. This compound se'parates as a heavy oil and is readily removed from the water layer. The ester is then treated with fresh Water in order to wash out any excess of acid that might be present.

' The oxalyl-phenyl-acetic-acid-ethylester may be converted into phenyl-malonic-acidethylester by splitting off carbon monoxide and subsequent distillation.

I do not wish to limit myselfto the exact proportions or details given in this example. For instance, I may proceed in the following way:

After the'semi-solid mass has formed, a portion of the alcohol in the charge may be distilled off and theresidue, when cold, converted into oxalyl-phenyl-acetic-acid-ethyles ter with cold dilute 'muriatic acid withlittle variation in the final results. The semi-solid mass may likewise be placed on a filter and the alcohol filtered off, leaving the solid sodiumoxa-l lphenyl acetic acid ethylester. This pro not can be treated with cold dilute muriatic acid and converted into the oxalylphen l-acetic-acidethylester.

I c aim:

1. The process which comprises causing a phenyl-acetic acid-aIkyIester to react with an oxalic-acid-dialkylester in the presence of sodium-alcoholate and dry alcohol. 1

2. The process which comprises causing a phenyl-acetic-acid-alkylester to react with an oxalic-acid-dialkylester in the resence of sodium-alcoholate and dry alcoiiol and treat- 15 ing the sodium-phenyl-oxalyl-acetic-acid-alky ester thus obtained with a free acid.

8. The process which comprises causing phenyL'acetic-acid-ethylester to act upon 01(- alic-acid-diethylester m the presence of sono dium-ethylate and dry ethylalcohol.

4. The process which comprises' causing. phcnyl-acetic-acid-ethylester to act upon oxalic-acid-diethylster in the resence of sodiu'm-ethylate and dry ethylal cohol and treata the sodium-phenyl-oxalyl aceticracid e ylester thus obtained with a free acid.

5. The rocess which comprises causing oxalic-aci -diethylester to act upon phenylaoetic-acid-eth lester in. the presence of sos dium-ethylate in about molecular proportions while using dry ethylalcohol as t e reactionmedium.

6. The rocess which comprises causing oxalic-acidiethylester to act upon phenyluacetic-acid-ethylester in the presence of sodium-ethylate in about molecular proper tions while using dry ethylalcohol as the reaction-medium and treatlng the sodium-oxalyl-phenyl-acetic-acid-ethylester with cold dilute acid.

In testimony whereof, I aflix my signature. RUFUS H. PRITGHETT. 

